like michael keaton, val kilmer. christian bale? >> i talked to clooney. he had advice which is not repeatable. i talked to christian. he said to make sure i got a zipper in the tut. it was valuable, practical advise. >> reporter: "batman versus superman, dawn of justice." >> it's easier to say. >> reporter: while mankind grapples with the hero it really needs. >> he has the pow or the wipe out the entire human race. >> reporter: why the bad blood? >> um, well, i mean, when sups turns up, he shows himself, he makes a bit of a mess. i would say bruce is one of the few people that thinks i could find a way of stopping this guy, if need be. i think it's out of -- just being careful. >> reporter: can this be a fair fight? gamts. how sit a far fight? >> it's not. interesting. >> how do you do that? >> he takes advantage of fact gnat supererman is a good guy, basically. >> reporter: but superheroes are not bit in a day. the leading men training for a year before stepping into their suits. >> i saw the first movie he was in. it was kind of like, wow. i don't know